Indicating instrument



April 10, E A. KE

INDICATING INSTRUMENT Filed Sept. 14, 1951 INVENTOR.

United States Pater-11:0

INDICATING INSTRUMENT Edward A. Kern, McClure, Ohio Application September 14, 1951, Serial No. 246,657

2 Claims. (Cl. 324-140) This invention relates to electrical instrumentalities utilizing magnetic circuits, more particularly to electrical indicating instruments.

In magnetic circuits where hysteresis loss is an important factor, the utilization of new alloys having low hysteresis loss is necessary, yet such alloys are hard and intractable materials which are diificult to fabricate in suitable forms for use in magnetic circuits. Then too, these new alloys are expensive, so that, in mass production of these electrical instrumentalities, it is essential to use a minimum amount of these alloys to maintain costs as low as possible.

This invention contemplates the provision of a structure for a magnetic circuit for use with an electrical instrumentality which utilizes a minimum quantity of an alloy having desirable magnetic characteristics, which, is in a simple form, suitable for fabrication in mass production from such alloy which is hard and intractable and not suitable for the usual manufacturing processes such as drawing or turning.

It is, therefore, a principal object of this invention to provide a magnetic circuit for use in electrical instrumentalities which is simple in form for each fabrication from hard intractable materials, which will allow the use of a minimum of such alloys to reduce costs.

It is a further object of this invention to improve the operating characteristics of an indicating instrument for use with an automobile.

Other objects and advantages of this invention relating to the arrangement, operation and function of the related elements of the structure, to various details of construction, to combinations of parts and to economies of manufacture, will be apparent to those skilled in the art upon consideration of the following description and appended claims, reference being had to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views.

Referring to the drawings:

Fig. l is a sectional elevational view of an instrument incoporating the invention;

Fig. 2 is a front elevational view taken from left of Fig. 1;

Fig. 3 is a perspective view of the elements of the instrument;

Fig. 4 is a perspective view of one of the elements; and

" Fig. 5 is a perspective view of another of the elements 2,741,743 Patented Apr. 10, 1956 having two components active approximately degrees apart to influence the position of an armature A as is Well known in the art and shown in Patent No. 2,507,801. Each stud 14 and 16 threads an aperture 20 in a triangular plate 22 of magnetic material which depends and is supported by the studs to form a magnetic return path as will be described further hereinafter. A magnetic tubular member 24 is next positioned on each of the studs above the plate 22, with which it comes into close contact for transfer of magnetic flux and to physically hold it in position. A spool-shaped magnetic coil 25 is mounted on each sleeve backed by a spacer washer 25A as shown. Then a pair of pole pieces 26 and 28 are threaded on the stud by apertures 30 to contact the end of the members 24 and finally a brass face plate (non-magnetic) 32 is positioned on both studs which is then peened over at its forward end to hold the whole assembly permanently together.

The magnetic members, including the triangular plate 22, tubular member 24 and pole pieces 26 and 28 are made from a special alloy known commercially as alloy No. 48 made by Armco Steel Company of Middletown, Ohio, and comprises a mixture of 48% nickel and the remainder pure iron, including traces of other elements. The alloy No. 48 is very intractable and cannot be conveniently or cheaply shaped by normal commercial practices such as turning etc. and can most cheaply be obtained in sheet form, from which all of the above parts are stamped, and then formed to their shapes as shown.

The triangular plate 22 is provided with an attenuated portion 22A which is connected to a pole portion 223 of arcuate conformation to the main body so as to allow adjustment by bending to control their air gap with the armature A, as is best seen in Fig. 2. The pole pieces 26 and 28 and the arcuate portion 22B are all positioned adjacent the locus of a cylinder, within which the armature A is adapted to move in response to the varying fields created by the coil 25 on the studs 14 and 16.

The pole pieces 26 and 23 are complementary with reference to the locus of the cylinder aforementioned, being formed on one edge with arcuate portions forming flanges 26A and 28A (see Fig. 5) which cooperate with the armature A. Behind the arcuate flanges 26A and 28A, adjusting fingers 26B and 28B are provided to allow ready cooperation with a manually-operable tool to rotate the pole piece about the ends of studs 14 and 16 to adjust the air gap with the armature A.

The non-magnetic plate 32, which is the last element of the stud assembly, has a cut-away portion 32A adjacent the armature A to provide two depending members 3213 vwhich are bent back to horizontal position to support an integral bearing bar 32C extending vertically therefrom as shown. Bearing aperture 34 is provided to seat the pintle 36 of armature shaft 38 adjacent a central position of the bar 32C adjacent the locus of the center of the aforementioned cylinder in which the armature A rotates.

The forward pintled end of the armature shaft is journaled in an aperture 32 in a depressed portion of a nonmagnetic supporting plate 4-!) cut away adjacent the armature to provide an aperture 42, through which extends the pointer P, which is attached to the shaft 33 adjacent the armature. The plate 4%) is attached to the inner plate 32 by a pair of screws 44-, engagin' apertures in a dial plate D and also elongated slots 46 in the plate 40 and then threaded into aligning apertures 48 in the inner plate 32. The tightening of the screws holds the plate 49 in adjusted position and also holds the dial D in position.

The armature A is in the form of a truncated circular disc press-fitted to shaft 38 and provided by backing weights 38A which provide a zero return by pull of gravity.

3 The two coils mounted on the'studs 14 and 15 are given an appropriate number of turns, the right coil (Fig. 2) being connected with a variable resistance and battery (not shown) to indicate a physical condition, as is well mounted concentrically on a stud projecting normally frcma base member in parallel relation with each other, tubular magnetic members of an intractable nickel alloy mounted on said studs and extending through said coils to carry the magnetic field created thereby, a unitary e r magnetic member including a normally positioned arcuate f ce portion lying in the locus of a cylinder C011- gig g g nested thereto by a bendable attenuated portion to allow n e 1 a 2,245,781 Hickok June 17 1941 a. ustment and cooperating by a touching relation with 2 507 801 Middleton y 1950 one end of both of said tubular members, said unitary magnetic member being supported by the studs adjacent the base member, a pair of magnetic pole pieces having arcuate flange portions lying in the locus of said cylinder including fingers in parallel spaced relation to the flange portions and adjustably affixed to the outwardly extending known in the art, while the left coil is connected in 5 end portions of the studs in touching relation with the parallel with the battery to provide compensation for ends of the tubular members, said fingers being adapted voltage variation. The temperature compensation is infor manipulation with simple tools to allow angular adherent in the construction and will not be further .disjustrnent of the pole pieces with relation to the locus of cussed. the cylinder, and an armature assembly adapted'to ro- A pair of insulated binding posts 59 are provided to tate adjacent the center of the cylinder in Whose locus connect the instrument into an external circuit by conthe unitary magnetic member portion and the pole piece necting the coil leads to a connector car 52 provided flange portions are positioned to respond to the variable with a pair of fingers 52A and 52B. The coil lead 54 is magnetic field created by the coils, said magnetic memwrapped about the first finger 52A and then the free end bers subject to the magnetic field including the tubular is soldered permanently to the second 5213 as shown. The magnetic members being all made of the same intractable relatively loose wrappin about the first finger gives a nickel alloy from sheet stock. resilient anchor for the lead, which, when subjected to 2. In a device of the class described, a pair of elecincessant vibration, is less likely to crystalize the metal tromagnetic coils creating a variable magnetic field each in the lead and cause breakage thereof. mounted concentrically on a stud projecting normally The construction disclosed hereinbefore has a magnetic from a base member in parallel relatiml with a other, circuit fabricated from special alloys which often do not tubular magnetic members of an intractable nickel alloy have physical characteristics which are adaptable to. mounted on said studs and extending through said coils methods employed in mass production. The elements of to carry the magnetic field created thereby, a unitary the magnetic circuit here are all fabricated from sheet magnetic member including anormally positioned arcuate stock from readily formed stampings, all of whi h are face portion lying in the locus of a cylinder connected to suitable for ready and cheap fabrication by such methods the main portion by a bendable attenuated element to of mass production. V allow adjustment and cooperating by a touching relait is to be understood that the above detailed description with one end of both of said tubular members, said 'tion of the present invention is intended to disclose an unitary magnetic mfimbef being supliofted y the Studs embodiment thereof to those skilled in the art, but that i t h base member, a p ir f'm gnc i pole pieces the invention is not to be construed as limited in its aphaving arcuate flange portions lying in the locus of said plication to the details of construction and arrangement Cylinder including IeaYWaIdlY posi i edfingcrs in parof parts illustrated in the accompanying drawings, since lcl pa d relation to the fiangeportions and adjust-' the invention is capable of being practiced and carried. F y affixed to The r ly eXteIlding end p rtions out in various ways without departing from the spirit of 39 of the studs in touching relation with the tube ends, said the invention, The language used in the e ifi ati r fingers being adapted for manipulation with simple tools 7 lating to the operation and function of the elements of to allow ngular adjustment of the pole pieces with re the invention is employed for purposes of description and ti H t0 th l cus Of the Cylinder, and an armature asnot of limitation, and it is not intended to limit the Scope Sembly including journal means to adapt the armature to of the following claims beyond the requirements of the 40 rotate adjacent the center of the cylinder in whose locus prior art. r the unitary member portion and the pole piece flange por What is claimed: tions are positioned to respond to the variable magnetic 1. In a device of the class described,- a pair of elecfield created y the Coils, Said magmatic members sublfict trornagnetic coils creating a variable magnetic field each the magnetic field including the tubular magnet bers being all made of the same intractable nickel alloy from sheet stock.

References Cited in the file of this patent UNITED STATES PATENTS 

